What are the power requirements for a SEM-Honeywell/ADEMCO Vista?

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Measuring panel voltage is a common troubleshooting step when experiencing odd behavior on a panel. Most often, this step is required when there is a Modem-Panel Comm message, or the panel is not communicating properly with Alarm.com. For more information about measuring the voltage, see Measure panel and module voltage.

Power requirements

Caution: Voltage outside of 16.5 -18 V range could cause modem-panel communication trouble.

The following table displays where to test voltage and what the recommended voltage is for the SEM-Honeywell/ADEMCO Vista:

Panel power requirements	16.5 VAC
Where to measure panel voltage	Terminals 1 and 2 on the main panel board.
Alarm.com module power requirements	12-13.5 VDC
Where to measure module voltage	The 12V and Ground (GND) terminals on the module gateway board.
Battery requirements	12V, 4Ah

For more information about power budget for specific devices, see SEM-Honeywell/ADEMCO Vista - Power Budget Calculator.

Wire size and maximum length

The following table displays the typical maximum wire length by gauge size that can be used to connect Alarm.com cellular modules to modular panels (i.e., DSC PowerSeries Neo/Pro, Interlogix Concord, NX, System Enhancement Modules, etc.).

Gauge	Length
22 gauge	40 feet (12.2 meters)
18 gauge	90 feet (27.4 meters)

Note: Doubling wires and Cat5e cables (and its variants) are not supported. For more information about using Cat5e cables, see Can Cat5e cables be used to connect Alarm.com cellular modules to panels?.